Elastic composite structure

ABSTRACT

An elastic composite structure including an elastomer system comprising at least one of a polyurethane resin, a polyurethane dispersion, or a silicone-based elastomer material. A mechanically durable reinforcer system includes a fabric, weave or knit structure including a flexible hybrid yarn including at least elastic polymer fibers, wherein the fabric, weave or knit structure is at least partially precoated/impregnated with an elastic and soft elastomer matrix to form a surface layer of the composite structure.

FIELD OF THE INVENTION

The invention relates to an elastic composite structure, which isintended for use as a flexible, pliable and thin film structure in themanufacture of a 2-or 3-dimensional product, particularly for providingmechanical protection against cutting, puncturing and/or the like. Theabove type of elastic composite structures can be exploited e.g. intextile products for applications relating to health service and healthcare industry, as well as in a number of other contexts.

BACKGROUND OF THE INVENTION

In reference to the prior art, e.g. Patent publications EP 0,318,415,U.S. Pat. No. 5,230,937, U.S. Pat. No. 3,974,320, U.S. Pat. No.5,447,594, U.S. Pat. No. 4,338,370, and JP 6278247 disclose structures,which are based on fabric or non-woven constructed plies of material.All of the above are inadequate in terms of their functions, especiallydue to their lack of strain or stretching property, and henceinapplicable for the manufacture of products which particularly requireelasticity. The reason for this is that the fabric or non-wovenstructures used in such products are only capable of providing pliableor flexible constructions, which are not, however, actually stretchable.The foregoing applies also largely to the solutions disclosed in Patentpublications JP 62297333, JP 11172860, and JP 1096227, all of which arenot necessarily provided with a so-called fabric or non-woven structureas a reinforcement but, for example, with carbon fiber systems or thelike. Even these solutions cannot enable the manufacture of a 2- or3-dimensional elastic product, since the discussed solutions are onlycapable of producing pliable structures. All the foregoing solutions maybe able to produce even highly flexible structures, yet incapable ofproducing structures which would be uni-, not to mention bi- ortriaxially stretchable, as required by elasticity.

The prior art further discloses the implementation of structuresprovided especially with a fabric-based reinforcement structure, e.g. asset forth in Patent publications WO 9200343 or JP 60259682. Even at itsbest, the strain provided by these solutions is less than 36%, whichrestricts significantly the usefulness of such solutions in themanufacture of products requiring special elasticity. The inadequatestrain properties and high module of elasticity result from and arebased on the fact that the fabric structures used in connectiontherewith are consistent with traditional technology. Thus, a sufficientelasticity is not provided thereby, since in practical applications,particularly with regard to the demands of health care industry, theminimum requirement for elasticity is easily about 100%.

SUMMARY OF THE INVENTION

It is an object with an elastic composite structure of this invention toprovide a decisive improvement over the foregoing problems and, thus, toraise substantially the current state of the art.

The most important benefits gained by an elastic composite structure ofthe invention include the simplicity of its construction andmanufacture, which enables the manufacturing of products with very highelasticity, yet provided with sufficiently good mechanical strengthproperties, particularly against puncturing, cutting and/or the like.The inventive elastic composite structure is optionally feasible with awide variety of constructions, the reinforcement system included thereinbeing first of all constructible as a fabric, weave or knit structuremade from a hybrid yarn, or else as an oriented flake reinforcementstructure made from laminated flakes. In a preferred embodiment, theinventive fabric, weave or knit structure, shielded e.g. with aparticularly elastic protective matrix, makes use of a hybrid yarn woundfrom rigid and elastic polymer fibers, thus effecting the maximizationof an elasticity resource between friction points in a fabric, weave orknit structure. The inventive construction is also feasible by using oneor more hard polymer layers, which is also integrally provided with anelastomer matrix for creating an elastic structure. It is furtherpossible to exploit the invention as so-called combination structures byproviding the same with both fabric-, weave- or knit-structured andlaminate-structured reinforcement layers along with an elastomer matrix.

Thus, the inventive elastic composite structure offers a solution, whichdiffers essentially and favourably from traditional solutions and whichis applicable even in highly demanding conditions, e.g. in garments wornin the context of hospital hygiene as such, without separate andmultilayer solutions dressed on top of each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with reference made to theaccompanying drawings, in which

FIGS. 1 a and 1 b show a few preferred principles for an elasticcomposite structure of the invention, regarding particularly aknit-structured reinforcement system,

FIGS. 2 a–2 c show a few optional constructions for an elastic compositestructure of the invention, regarding particularly a fabric-, weave- orknit-structured reinforcement system,

FIGS. 3 a–3 c show further a few preferred optional solutions for anelastic composite structure of the invention, regarding particularly areinforcing flake-structured reinforcement system,

FIGS. 4 a–4 d show further preferred embodiments for an elasticcomposite structure of the invention in the way of so-called combinationstructures, and

FIGS. 5 a and 5 b show further a few preferred constructions for anelastic composite structure of the invention, which have been producedby means of certain types of manufacturing techniques.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention relates to an elastic composite structure, which isintended for use as a flexible, pliable and thin film structure in themanufacture of a 2-or 3-dimensional product, particularly for providingmechanical protection against cutting, puncturing and/or the like. Thecomposite structure comprises firstly an elastomer system 1, which isconstituted by one or more qualitatively different PUR- (polyurethaneresin), PUD- (polyurethane dispersion), SI- (silicone) based elastomermaterials and/or the like, and secondly by a mechanically durablereinforcer system 2, such as a fabric, weave or knit structure 2 a madefrom one or more flexible hybrid yarns, an oriented flake reinforcementstructure 2 c made from laminated flakes y, and/or the like.

In a particularly preferred embodiment, a fabric structure, or the typeof knit structure 2 depicted by way of example in FIGS. 1 a and 1 b,included in the reinforcement system of a composite structure, ismanufactured from a hybrid yarn L wound from rigid and elastic polymerfibers L1, L2, such as liquid crystal polymer (LCP) and elastane fibers,particularly for the maximization of an elasticity resource x betweenfriction points fp present in the fabric, weave or knit structure 2; 2a. This way, it is even possible to achieve a strain of e.g. 500%between the friction points. The hybrid yarn L is also relaxable e.g. bythe application of heat, whereby the threaded multifilament structurethereof retains its carriage more effectively and provides the knitstitch with a proportional specific elasticity which is better than thatobtained with a non-relaxed yarn. The manufacture of a hybrid yarn canbe effected by using various fiber materials and systems, such asorganic and inorganic fibers, mono- or multifilaments, for a variety ofultimate properties.

A knit structure constituted by the hybrid yarn L may be “overelastic”prior to coating, in spite of which, since the knitting loses some ofits elasticity in the coating process, it is preferable that the hybridyarn and the knitting be provided with as much of elasticity resource aspossible in the above-described fashion. Naturally, a hybrid yarn canalso be used for producing fabrics, weaves or the like.

In a preferred application, especially in reference to the embodimentsdepicted in FIGS. 2 a–2 c, a fabric 2; 2 a′ or knit structure 2 aincluded in the reinforcement system of a composite structure isprecoated/-impregnated partially or entirely with an elastic and softelastomer matrix 2 b, which, at a strain of 100%, has a modulus ofelasticity of 1.0 Mpa or less, particularly for protecting the hybridyarn L and the friction points fp of the fabric, weave or knit structure2; 2 a, or for retaining the optimal elasticity feature of the fabric,weave or knit structure by forming the composite structure's actualsurface layer 1 on top of the soft elastomer matrix 2; 2 b.

In a further preferred embodiment, the elastomer matrix 2; 2 b of thefabric 2 a; 2 a′, weave or knit structure 2 a is fabricated on amulticomponent principle by firstly pretreating the fabric, weave orknit structure locally or entirely with a first component, the fabric,weave or knit structure being secondly further coated with a blend ofcomponents, such as by dipping, spraying and/or in a like manner, byusing a blend of components containing a second and third component,whereby, during the coating process, the second component has reactedwith the first component so as to produce a soft and elastic matrix 2; 2b around/on top of the fabric, weave or knit structure 2; 2 a, and thethird component has produced a mechanically more durable surface layer 1on top of the soft elastomer matrix.

In this context, the first component may comprise e.g. a prepolymer, thesecond component may be a crosslinker or a chain extender/former, and,furthermore, the third component can be a neutralized, inertpoly-/elastomer.

Naturally, the above type of composite structure can also be preparedfrom a fabric, a weave or the like by coating as described above. Thecomposite structure has a reinforcer content in the matrix preferablywithin the range of 5–95% by volume. With an optimized structure, it ispossible to attain similar elasticity properties both in lengthwise andcrosswise directions of the structure. This way, it is possible to varythe elasticity feature of a structure even over the range of 100%–1500%.

On the other hand, the invention relates to an elastic compositestructure, which is intended for use as a flexible, pliable and thinfilm structure in the manufacture of a 2- or 3-dimensional product andwhich comprises a reinforcement system 2 for mechanically reinforcingthe same against cutting, puncturing and/or the like. The reinforcementsystem 2 for a composite structure of the invention is prepared as aflake reinforcement system 2 c, consisting of hard organic and/orinorganic materials and having its flakes y arranged as one or more hardpolymer layers and, which contain an elastomer matrix 2; 2 b adapted toprovide the elastic structure with an integral composition. In thiscontext, reference is made especially to FIGS. 3 a–3 c, all of whichnevertheless include also the actual surface structure 1.

In a further preferred embodiment, the flake reinforcement for acomposite structure of the invention is manufactured from a hard organicand/or inorganic material, having a surface area which is preferably >2mm² and a thickness which is within the range of 0,02–1 mm, preferablyby laminating from one or more hard polymer layers and by providing thelaminated structure preferably also with extra reinforcements, such asan extremely thin and dense non-woven or fabric reinforcer or the like.

Preferred applications for this type of arrangement include e.g. thefollowing solutions, wherein the flake reinforcement system 2; 2 c isdesigned as an integral and comprehensive mechanical protective layer,in which one or more structural layers of the flake reinforcement systemare established:

-   -   by applying the flakes y with mechanical and/or manual        orientation to the surface of an elastomer coating 1;    -   by applying the flakes y to the surface of an elastomer coating        1 electrostatically by spraying along with the soft elastomer        coating 2; 2 b;    -   by applying the flakes y with free orientation to the surface of        an elastomer 1; or    -   by applying the flakes y electrostatically “or pneumatically so        as to locate the same as desired to constitute a desired type of        orientation layer 2 c; 2 c” prior to a subsequent elastomer        coating 1, this application being depicted especially in FIG. 5        a.

Referring especially to what is described above, orientation of theflakes y is most preferably carried out electrostatically in such a waythat the flakes y have been polarified for a desired orientation byusing, as an orientation pattern, a so-called imbricate structure or thelike as shown e.g. in FIG. 3 a or 3 b, or else a free orientation 2 c; 2c′ as shown e.g. in FIG. 3 c.

In the preferred embodiments shown especially in FIGS. 4 a–4 d, thereinforcement system 2 included in a composite structure has beenprepared from a combination of reinforcements, comprising the fabric,weave and knit structure 2 a and the flake reinforcement layers 2 c.

As a further preferred application, the flake reinforcement composition2 c is attached in this type of embodiment to the fabric, weave or knitstructure 2 a by means of an anchoring technique, the flakereinforcement being treated with a first component and the fabric, weaveor knit structure, respectively, either comprehensively or locally, witha second component for providing a desired adhesion between the fabric,weave or knit structure and the flake reinforcement at a desiredlocation.

In particular reference to the construction shown in FIG. 5 b, a flakereinforcement system 2 c; 2 c′ is provided on top of a fabric, weaved orknitted structural layer 2 a, coupled with an elastomer coating 1, so asnot to restrain the elasticity of the fabric, weaved or knittedstructural layer, by the application of a multicomponent principle orthe like, the flake reinforcement being treated with a third component,which does not provide an adhesion with the fabric, weave or knitstructure 2 a, or with a yarn L used therein.

It is obvious that the invention is not limited to the applicationsdescribed or depicted above but, as disclosed in the following examples,it can be applied in most diverse variations. Thus, particularly cuttingproof structures as shown especially in FIGS. 2 a–2 c, as well aspuncture-proof structures as shown especially in FIGS. 3 a–3 c, or elseboth cutting- and puncture-proof structures as shown in FIGS. 4 a–4 cmay of course be prepared by the application of most diversemanufacturing techniques, e.g. in such a way that such structures arepre-designed with a certain type of surface texture, such as groovepatterns, nodule patterns or the like. In addition, the use of suitablemanufacturing techniques, such as electrostatic coating, also enablesthe preparation of perfectly three-dimensional products, such as glovesor the like, which additionally provide a so-called perfect fit in sucha way that, instead of tubular forms, the manufacturing process is setto produce structures having cross-sections which vary in thelongitudinal direction thereof. Furthermore, the type of elasticityprinciples depicted particularly in FIGS. 2 a and 2 b will be fulfilledalso in the case of fabric-, weave- or web-structured texture structureby using a twisted hybrid yarn.

1. An elastic composite structure, comprising: a mechanically durablereinforcing layer comprising an elastic fabric, weave or knit structureincluding a flexible hybrid yarn comprising rigid and elastic polymerfibers, the reinforcing layer further comprising an oriented flakereinforcement structure comprising laminated flakes, and wherein theflake reinforcement is treated with a first component and the fabric,weave or knit structure, is treated comprehensively or locally with asecond component for providing a desired adhesion between the fabric,weave or knit structure and the flake reinforcement at a desiredlocation; an elastic protecting matrix for the reinforcing layer, theelastic protecting matrix comprising an elastic and soft elastomermatrix at least partially coating/impregnating the fabric, weave or knitstructure of the reinforcing layer, the elastic protecting matrix beingoperative to retain elasticity of the reinforcing layer; and a surfacelayer comprising an elastomer system covering the elastic protectingmatrix and the reinforcing layer, the surface layer comprising at leastone of a polyurethane resin, a polyurethane dispersion, or asilicone-based elastomer material.
 2. The composite structure accordingto claim 1, wherein the structure is a flexible, pliable thin structure.3. The composite structure according to claim 1, wherein the structureis operative in the manufacture of a 2-or 3-dimensional product.
 4. Thestructure according to claim 1, wherein the structure providesmechanical protection against cutting and puncturing.
 5. The compositestructure according to claim 1, wherein the elastic polymer fiberscomprise elastane fibers.
 6. The composite structure according to claim1, wherein the rigid polymer fibers comprise liquid crystal polymer. 7.The composite structure according to claim 5, wherein the elasticpolymer fibers maximize an elasticity resource between friction pointspresent in the fabric, weave or knit structure.
 8. The compositestructure according to claim 1, wherein the soft elastomer matrixprotects the hybrid yarn and the friction points of the fabric, weave orknit structure.
 9. The composite structure according to claim 1, whereinthe soft elastomer matrix retains a maximum elasticity feature of thefabric, weave or knit structure.
 10. The composite structure accordingto claim 1, wherein the flakes comprise at least one of hard organic orinorganic materials, wherein the flakes are arranged as one or more hardpolymer layers including an elastomer matrix adapted to provide theelastic structure with an integral composition.
 11. The compositestructure according to claim 1, wherein the flakes are polarified for adesired orientation by using, as an orientation pattern, an imbricatestructure, or a free orientation.
 12. The composite structure accordingto claim 1, wherein the flake reinforcement system is provided on top ofthe fabric, weave or knitted structural layer.
 13. The compositestructure according to claim 12, wherein the flake reinforcement systemdoes not block the elasticity of the fabric, weave or knitted structurallayer.
 14. The composite structure according to claim 12, wherein theflake reinforcement system is provided by application of amulticomponent principle, wherein the flake reinforcement is treatedwith a third component that does not adhere to the fabric, weave or knitstructure, or with a yarn used therein.
 15. The composite structureaccording to claim 1, wherein the flake reinforcement system comprisesan integral and comprehensive mechanical protective layer, wherein theflakes are applied with mechanical and/or manual orientation to thesurface of an elastomer coating, applied to the surface of an elastomercoating electrostatically along with the soft elastomer coating, appliedwith free orientation to the surface of an elastomer, or appliedelectrostatically or pneumatically so as to locate the flakes as desiredsuch that the flakes constitute a desired type of orientation layerprior to a subsequent elastomer coating.